The Digital Satellite Service (DSS) has become increasingly popular among consumers, permitting viewers in sparsely populated or mountainous areas high quality access to television programs from around the world. Residents of areas too distant from a ground transmitter to receive high quality television signals, residents of areas where delivery of television signals by cable is impractical, and residents of mobile homes and recreational vehicles moving from one location to another, can receive television programs wherever they happen to be. Television transmitters operating in the DSS system provide coded digital signals via a satellite to receivers located within the field of view of the satellite. The satellite or satellites in the DSS system retransmit a signal from one or more earth stations to a large number of receiving earth stations. Satellites in geo-stationary orbit, or a series of satellites passing through positions over the United States, can provide continuous television programming to viewers, anywhere in the country.
DSS receivers generally are low-cost, simple to connect, small and easily transportable parabolic antennas that consumers mount on a residential rooftop or recreational vehicle. To set up a DSS antenna, a viewer determines the defined elevation and azimuth angles from the antenna location to the satellite. The coarse directional angles to the satellite in the satellite's field of view from any point on the earth can easily be determined by a customer setting up a receiver location. Once the angles are determined, the viewer points the antenna toward an approximate point in the sky in the neighborhood of the satellite, and begins the adjustment or "fiddling" process of moving the antenna in slight movements until the reception at the television is clear. In the case of a mobile receiver unit, this process must be repeated at each location. However, because different viewers live in different parts of the country, or can move from one place to another, assisting a typical consumer with correct and accurate pointing of an antenna toward a satellite has become a necessary element of the DSS system.
The elevation and azimuth angles are available for each longitude and latitude, as well as for each zip code. Hence, a dish installer can usually point the antenna in the general direction of the satellite. However, the antenna may still be difficult to position accurately, for a number of reasons. Fine angle discrimination is difficult, due to the measurement errors of determining one's precise longitude and latitude, the range of locations that may be within a zip code, and even mechanical bending of the structure supporting the antenna. Mechanical bending of the structure causes an error that is difficult to measure and correct, since it may introduce a roll component as well as an unmeasured azimuth and elevation angle. The viewer may also create orientation errors, for example by installing the antenna support structure on a roof that is not completely horizontal, or, if the antenna is mounted on a recreational vehicle, by parking on an uneven site. If the base of the antenna structure is not placed on a truly horizontal stable support, required elevation angles, such as "42 degrees above the horizontal", are exceedingly difficult to implement.
In the DSS system, the antenna is generally coupled to a receiver via a cable. The receiver then provides the signal to the television or other viewing monitor. To accommodate different viewer's locations, for example mountainous or urban locations with large structures that may interfere with line-of-sight reception from the satellite, the cable provided is long enough to allow the antenna and the receiver/television to be some distance apart. To orient the antenna properly, therefore, the viewer sets the antenna in a selected location, directs the antenna toward the general orientation angles (azimuth and elevation) as reported for the location of the antenna. Once the antenna is set in the location, the viewer must then make minor adjustments to the antenna orientation, often by only fractions of a degree, to receive a clear video image. Unfortunately, the physical distance between the television and the antenna make this precision adjustment difficult. From the vantage point of the antenna, the television is remote, i.e. too far to see clearly, and the line of sight is generally interrupted by walls and other objects. Generally, the viewer has three options for adjusting the finer gradations in the orientation of the antenna: he can make repeated trips between the antenna and the television; he can enlist the aid of another person to watch the television and report orally on how clearly the signal is being received, either by calling out loudly enough to hear or by using a two-way radio (i.e., a walkie-talkie); or the viewer can hire an installation service. These solutions all have problems, however. The repeated trips between the television and the antenna, for example, can take a very long time and are frustrating. The second solution is not satisfactory either due to the difficulty in describing the clarity of a picture in measurable terms. Also, many people live alone or in remote areas, and one of the most important features of DSS is its ability to provide clear television pictures to remote areas too sparsely populated to attract cable companies. The third solution can be prohibitively expensive, and also may be unavailable to people living in remote areas.
A commercially available system that attempts to resolve these problems employs a single blinking light at the antenna to indicate signal strength. As the dish is moved, changing the signal strength, the receiver connected to the antenna provides a signal up the cable to the light at the antenna. This signal causes the light to blink slowly to indicate low received signal strength, and faster blinking to indicate higher signal strength. When the light is steady, the antenna is supposed to be positioned correctly.
The problem with this known system is the non-intuitive nature of the signal strength indication afforded by the blinking light. As one moves the antenna in minute increments, it is difficult to accurately judge whether an adjustment causes the light to blink at a slightly faster frequency, or a slightly slower frequency. Further, once the antenna is adjusted so that the light is steady, there may still be some adjustment that could be made to improve the signal reception to a maximum level.
Due to the versatility of the DSS devices, however, satellite antennas and receivers are very popular, notwithstanding these difficulties. Nevertheless, the difficulties inherent in the initial orientation of the antenna upon setup are problematic to many viewers.